Automatic train-control system



S. D. RODGERS. ,AUTOMATIC TRAIN CONTROL SYSTEM. APPLICATION man NOV. 9, I9I6.

1,359,839. Patented Nov. 23, 1920.

I I I I I'I' lllllljlllll S. D. RODGERS. AUTOMATIC TRAIN CONTROL SYSTEM.

APPLICATION FILED NOV. 9 I916.

Patented NOV. 23, 1920 a SHEETS-SHEET 2 CH x5 x A INVENTOR WITNESSES s. D. RODGERS.

AUTOMATIC TRAIN CONTROL SYSTEM. APPLICATION FILED NOV. 9, 1916.

Patented Nov. 23, 1920.

3 SHEETSSHEET 3.

WITNESSES omreo srares STEWART PATENT omcei.

D. RODGERS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR OF ONE-FOURTH T0 CLARENCE Gr. HILDRETH, 0F PITTSBURGH, PENNSYLVANIA.

- AUTOMATIC TRAIN-CONTROL SYSTEM.

Application filed November 9, 1916. Serial No. 130,446.

venteda new and useful Improvement in Automatic T rain-Control Systems, of which the following is-a specification.

This invention relates to automatic train control systems. It is particularly applicable to steam railways in connection with the block signal systems thereof, but it'niay be also applied to other railways, such, for example, as electric railways.

The invention is adapted to be used with any suitable block system of railway sig;

naling and is designed to automatically prevent a train running past signals which have so that in case a train comes into a block immediately behind another train, a caution signal is first and later a danger signal is flashed .and

the brakes automatically applied to reduce the speed of the train to a safe controllable limit. In case the train. is not entirely stopped it is automatically stopped by a further application of the brakes: when the train reaches what is known as the stop sig nal station. A I

The invention is an improvement upon the system disclosed in my co-pendingapplica 'tion, filed April 24, 1915, Serial No. 23,710. ()ne of the objects of the invention is to provide an improved automatic train control system which will operate signals within the cab of the block ahead.

A further object is to provide an improved automatic" train control system in which the train will be automatically stopped in case of dangeron the block ahead even though the engineer does not see or disregards the signals.

A further object is to provide an improved train control system in which the,

speed of the train is reduced in case of danger ahead by setting the brakes and in which the brakes are automatically released as soon as the train 'gets down to a predetermined'slow speed.

,A further object is to provide an improved automatic train control system in which. when the train gets down to a predetermined slow speed, if'it is not stopped before reaching a certain point, it will be au+ of the brakes.

.for. 1

'Fig. 2 is aside elevation of the sema- .phoresof a block signal system, showing flashed in the engineers cab the engine in case of danger on 'track is clear. However,

Specification of Letters Patent. Pate t d N 23 1920 tomatically stopped by further application A further object is to accomplish all the above functions by means of an improved system in which it is un-necessar to have sections of the railway track-insu ated.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an the drawings are as follows:

. -I*1gure' 1 is a diagrammatic view of: the

a I embodiment of the invention. The views of r railway track and the track circuits tlierethe manner in which the semaphores control I '7 the circuits of the automatic train control been set against it. The system is arranged r y r I 75. diagrammatic view of the wirig. 4 is a side elevation and partial cross seotionof the contact shoe carried on the,

train.

Fig. 5 is aside elevation of the contact i shoe, the batteries and the switchboard for controlling the circuits.

tromagnets located along the track, said view Fig. 6 is a cross section of one of the elecshowing the position of the shoe carried on,

the train with relation to the magnet.

' Fig. 7 is-a. top plan view. of a portion of j one of the magnets located along the track. Thetrack circuits will first be described,

after which the operative apparatus on the It may be stated,

engine will be explained. however, that the signals and other apparatus on the engine are rendered operative by means of a shoe carried on the train which is attracted by' magnets located along the track. VVhenthe track is clear the magnets and therefore the train and consequently the apparatus on the engine is not operated as long as the when there is a train in the preceding block, the magnets in the blockcbehind are energized, and if a train'runs into this block the magnets attherealong are not energized u do not attract the shoes on tract the shoes on the engine and operate the apparatus carried thereby.

Referring to Fig. 1, the section ofrailway track between the point A and the point B constitutes one block of an ordinary block signal system, the direction in whic the trains run tliereover being indicated by the arrow. The invention can be used in connection with any system of block signaling, and Fig. 1 illustrates only the semaphores of such a system without showing the circuits for operating. them.

A block signaling system usually has one or more semaphores. two being shown in this instance, which are normally in upright position. as illustratedat the left-hand end of Fig. 1. These sema']')hores are controlled by trains in the block ahead of the oneillustrated in the drawings. that is. the block immediately to the left of the point B in Fig. 1. 'hen there is no train on the block at the left of point B. both the semaphores are in the position shown. 'hen there is a train in the block at the end thereof adjacent the point B, both the semaphores are down in a horizontal position, the combined position of the semaphores meaning danger,that is, when there is a train very close in the block ahead. hen the train has moved to the left-hand end of the block. one of the signals. the upper one in this case. moves up. but the other remains in horizontal position, the combined positions of the two semaphores being at such a time in what is known as f 'aution position. that is, they caution the engineer that there is a train 'in the next block, though it may be some distance away.

As hereinbefore stated, the semaphores shown in Fig. 1 are controlled by the block at the left of the point B. These semaphores are positioned, however, so as to' be observable from the block illustrated in Fig. 1.

It is. of course. to be understood that in some cases only one semaphore is used which has three positions, or more than one semaphore may be used with each semaphore located separately. The exact location and the number of the semaphores is not important in the present invention, since for an operation of the system herein described it is merely necessary to have electrical contacts associated with the semaphore or sema phores to control the circuits of the automatic train control system.

Near the right-hand end of the block shown in Fig. 1, is located an electromagnet 1 in a position relative to the block which is called caution position. At about the center of the block and on the opposite side of the track .is located an electromagnet 2 in what is called danger position. At the left-hand end of the block and on both sides of the track are. located electromagnets 3 and 4 in what is called stop position.

When the track is clear. all of these electromagnets are (ls-energized and have no effect upon the apparatus located on the passing train. When, however, there is a train at the right-hand end of the block im mediately preceding to the left, all of the electromagnets will bevenergized and the apparatus on a train coming into the block will be successively operated, first, by the caution magnet to give a caution signal, second. by the danger magnet to give a danger signal and apply the brakes, and finally by the stop magnets to further apply the brakes to stop the train. In case the train in the preceding block is almost off the block. only the mution magnet 1 will be energized and consequently the apparatus on a train coming into theiblock illustrated in Fig. 1 will be operated only as it passes the caution magnet to give a caution signal to indicate to the engineer that he should run carefully.

The circuits by means of which the electromagnets are supplied with energy will first be explained and then the manner in which the circuits are controlled by the semaphores will be described.

Each of the electromagnets is energized. preferably by a direct current (if-relatively low voltage, as for exainple, Ste 10 volts. They may. however, be energized by current of higher voltage or by alternating current, if desired. There may bear separate source of energy for each electromagnet, or a number of electromagnets may beenergized from a common source. In thepresent system energy is supplied to each of the electromagnets by storage batteries 5 which are located in the vicinity of the electromagnets. These storage batteries are supplied with energy from the direct current line 6 common to a plurality of the batteries and their electroinagnets located along the railway track. Energy is preferably supplied to the direct current line from an alternating current line 7 through a transformer 8 and rotary converter 9. 7

Each of the batteries has an amperehourmeter 10 associated therewith which, when the battery charge decreases below a predetermined amount, connects the battery to the direct current source. of supply to charge the same.

The circuits of-each of the electromagnets and their associated storage batteries and charging systems are substantially alike and therefore only one will he described in detail. The circuit of electromagnet 1 is as follows:

Current from the storage battery 5 passes through the shunt 11 of the amperehourmeter. the conductor 12, contact 13, and armature l-t of relaylfi when said relay is deenergized and the armature is in engagement with the contact 13, said armature being biased into engagement with said contact, when the relay is deenergized. by means of a spring 16. From the armature 14 current passes through conductor 17 to the electromagnet 1 and returns from the same through the conductors 18 and 19 to the opposite side of the storage battery. The electromagnet 1 is thus energized by the storage battery whenever the relay 15 is deenergized so that its armature is in engagement with the contact 13.

Whenever the energy of the storage battery decreases below a predetermined amount, a contact on the ampere hourmeter completes a circuit from the battery 5 through the conductor 20, the ampere hourmeter, the conductor 21, coil 22 of I the switch 23 and conductor 24 to the opposite side of the battery. This closes the electromagnetic switch 23 and connects the direct current supply directly to the electromagnet 1, and also connects said supply so as to charge the battery 5. In order to prevent the battery being connected to the direct current source of supply when the voltage of said supply is below the voltage of the battery. a switch 25 is provided, the coil'26 or" which is normally across the direct current supply wires 27 and 28. Vhen the voltage of the direct current supply is equal to or above the required minimum limit for charging the batteries the coil 26 pulls the switch closed. The switch 25 is normally biased to open position so that in case the voltage drops below the desired charging value, the switch is automatically opened.

i-Xssuming that both the switches 23 and 25 are closed, the current to the electromagnet 1 from the direct current supply line 6 is through conductor 28, switches 25 and 23. conductors 24 and 12, the armature 14 of relay 15, when said armature is in engagement with the contact 13, conductor 17. electromagnet 1, and conductors 18 and 27 to the other side of the direct current supply line. At'the same time the batteries are being charged from the supply line in a manner well understood.

The electromagnet 2 is connected to the direct current supply line 6 in a similar manner, its circuit being controlled by the relay 29. It is also provided with a storage battery 5 charged from the direct current supply line 6 through the usual battery charging system including an amperehourmeter 10.

The stop electromagnets 3 and 4 are connected in parallel to the direct current supply circuit 6 in the same manner as the other electromagnet-s. They are controlled by a relay 30 and have a storage battery 5 connected so as to supply energy to them and to be charged by the direct current line (5 through a battery charging system including an ampere hourmeter 10.

The circuits. of the electromagnets 1, 2, and 4 are controlled as follows:

1 The caution semaphore 31 and the danger semaphore 32 are each provided in this instance with an extension'for controlling the cuits of the electromagnets.

circuits of certain of the electromagnets. It is not absolutely necessary to have extensions directly on the semaphores for controlling the circuits, but some suitable arrangement should be provided so that when the semaphores move A relay in shunt to the relay of the ordinary block signal. circuit may be used for controlling the electromagnet' circuits.

The lower or caution semaphore 31 has an extension 33 which controls contacts 34 and Contact 34 is connected by means of conductor 36 to a source of energy 37, and contact 35 is connected by means of conthey control the-cirductor 38 to the relay 15 controlling the cir-' cuit of the caution" electromagnet 1.

The upper or danger semaphore 32 has an extension 39 which controls contacts 40 and 41. The contact .41 is connected to the source of energy 37. and the contact 40 is connected by means of conductor 42 to the relay 30 controlling the stop electromagnets 3 and -t. Contact. 40 is also connected through conductor 12 and conductor 43 to the relay 29 controlling the circuit of the danger electromagnet 2.

The opposite end of the winding of the caution relay 15 and the opposite ends of the windings of the danger" and stop relays 29 and 30 are connected to one of the rails of the track. to which rail is also connected the side of the source of the energy 37 opposite that to which the conductor 36 is connected.

It will thus be seen that the lower or caution' semaphore 31 controls the circuit of the relay 1:) which in turn controls the circuit of the caution electromagnet. The

danger semaphore 32 controls the circuits of the danger relay 29 and the stop relay 3() which in turn respectively control the danger electromagnet 2 and the stop clectromagnets 3 and 4.

Accordingly, when the track is clear and both 0t the semaphores are in their upright positions as illustrated. the circuits of all the relays are closed by the cont-acts on the semaphores, and consequently the armatures of all the. relays are attracted and the circuits of all the electromagnets are open so that these electromagnets are deenergized and theapparatus on a passing train is not affected. I

' If a train should he at the far end of the block to the left of the point B so that the caution semaphore 31 is down. the circuit including the contacts 34 and 35 will be open, and consequently the relay 15 will bedeenergized. as a result of which its armature 14 will be pulled over by a spring 16 into both the semaphores 31 and 32 are down,-the-. the'relays 15, 29 and will circuits of all be open, and consequently their arm-atures will be pulled over by the springs associated therewith into engagement with the respective contacts. and all the electromagnets 1,

2, 3 and 4 will be energized, so that any train coming into the block illustrated in the drawing,- will, as it passes-the successive electromagnets, have the apparatus on its engine operated so as to first give a caution signal, then a danger signal and an application of the brakes, and then a later application of thebrakes to stop the train. The apparatus carried by the engine is illustrated in Fig. 3 and is as follows The engine ortender or some car of the train carries two movable shoes 45 and 46, one on each side of the tender or car. The shoes are made of magnetic material and are arranged to be moved magnetically when they come into the vicinity of an energized electromagnet along the track. Each of the shoes is grounded to the frame of the tender or car upon which it is mounted so that there is normally an electric circuit from one shoe through the truck frame to the other. The shoe 45 is connected to a switch 47 normally biased into an engagement with a contact 48 by a spring 49. The shoe 46 is connected to a switch 50 normally biased into engagement with the contact 51 by a spring Located upon the engine, and preferably in the cab, is the green or c'aution'signal 53 and the red or danger signal 54. Also, located at suitable points on the train is the electromagnetic valve 55 for controlling the air brakes. I

Ilnergy is supplied for operating these various devices on the train by means of a battery 56, which is connected through the conductor 57, the relay winding 58, armature to the conductor 60, from which it goes in one direction through the relay winding 61, to conductor 62 and the shoe 45 to the truck frame, and in the other direction through the relay 63, the conductor 64 and the shoe 46 to the truck frame. The opposite side of the battery is connected by conductor 65 through-the reversing switch 66, the conductor 67, the pilot light 68 and the magnet winding 69 of the brake controlling valve to the truck frame and thence through shoes 45 and 46 to the opposite side of the battery. It will accordingly be clear that with the apparatus in the position shown,

position shown and the electromagnet 69 of the brake valve will beenergized to hold its plunger 70 in the position illustrated.

, there is also a circuit 63' will be in the- With the devices in the position shown from the negative side of the battery through the conductor 71, the armature 72 of relay 61, the conductor 73, the resistance 74, the conductor 75, the

switch blade 7 6 of the reversing switch, the conductor 77, the relay winding 78, a bridging contact 79 operated by the relay winding and the pilot light 80, the conductor 67, the middle blade ofthe reversing switch, and the conductor 65 to the positive side of the battery. 1

' There. is also a circuit from the negative side of the battery through the conductor 81, the armature 82 of the relay 63', the resistance 83, the conductor 84, switch blade 85 of the reversing switch 66, conductor 86,

relay winding 87, a bridging contact 88, operated by the relay winding, the conductor 89, relay winding 90, conductor 91, pilot lamp 92, and conductor 67 through the reversing switch to the positive side of the battery.

When, however, the train passes an energized caution electromagnet along the track, the shoe 45 is drawn down and the circuit of the relay 61 is opened by the switch 47. The relay 61 is thus momentarily dei nergized, allowing its armature 72 to be drawn back by the spring, and opening the circuit from the negative side of the'battery through the armature 72, conductors 7 3 and 75. and reversing switch tothe relay 78. The relay 78 is thus deenergized and its bridging member 79 drawn down by the spring associated therewith into engagement. with the contacts 93 and 94. This completes a circuit from the negative side of the battery. through the conductor 71, resistance 95, conductor 96, bridging member 79 of relav 78. conductor 97, the caution signal 53 to the engineer in case he is not looking at the signal. The circuit to the electromagnet 69 of the brake controlling means is still maintained and said means is not disturbed.

If the train new passes an energized danger electromagnet, the-shoe 46 is drawn down, opening the circuit of relay 63 and allowing its armature 82 to be momentarily withdrawn by the spring associated with it. This opens the circuit from the negative'side of the battery through the relay armature 82 to the relays 87 and 90. lVhen the relay 87 is dener ized, the bridging member 88' is drawn down by the spring associated therewith into engagement with the contacts 99 and 100. This completes a circuit from the negative side of the battery through the conductor 81, the resistance 101, conductor 102, the bridging member 88 of relay 87, the red or danger signal 54, the conductor 67 and the reversing switch to the positive side of the battery. A bell, or other andibles ignal 1031s connected with the vis'i- Y The electromagnet 104 is withdrawn by the'spring 105,

ble danger-signal 54 to draw the engineers attention to the danger signal in case he is not looking at the same.

Relay*90 is with the relay 87,

allowing the armature 106 to be drawn down by the spring 107 into engagement with the contact 108. This completes a circuit from the wire 67 through a conductor 109, armature 106, c0nductor'110, contact lever'111,

contact 112 and conductor 113 to ground.

art.

' It wil'l thus be clear that when the train passes an energized danger electromagnet the danger signal 54 is flashed and the electromagnet 69 is dee'nergiz ed to allow the train pipe pressure to be vented to apply the brakes.

The brake controlling means comprises an electromagnet 69 controlling a plunger 70, having a valve 114 on the end thereof for controlling comr nunication between the chambers115v and 116. The train pipe 117 adjustable screw magnet.

chamber 115. 45.

nected a, vent has a plurality of the air brake systemis connected to the The chamber 116 has an opening therein at one side to which is con- .valve 118. This vent valve of small holes therein for permitting pressure p chamber 116 gradually, the rate .at which the pressure'escapes being controllable by an 119. 'When the electro- 69 is, deenerg'ized the plunger 70 moves downwardly. and opens communication between the chambers 115 and 116.

ipe pressure toescape This allows the train from the pipe '117it rough chambers 115 and 116 a'ndfthe vent valve 118. -The pres sure escapes "very slowly, however, and the passes a danger signal be well understood.

brakes are only gradually applied,- as will ,Inasmuch as the brake controllingmeansis operated when the train the gradual application of the brakes slows down the speed of the train sufliciently to revent its running rapidly past the stop e ectromagnets,

deenergized simultaneously whereupon its armature 'The'downward movement of the to escape from they said electromagnets are deenergiz'edg Th.-

The speed responsive mechanism shown in the upper left hand corner of Fig. 2 is mounted on the engine or tender and. comprises an ordinary centrifugally operated governor suitably geared to the engine or tender. This governor controls the lever 111 which engages the contacts 112 and 120. When the speed of the train is reduced by an application of the brakes after the train runs past a danger signal, the speed governor moves the lever 111 upwardly andout of contact with the contact 112. The governor may be adjusted so that at a certain predetermined speed, for example, six miles an hour, the lever 111 stands between the contacts 112 and 120. The circuit to ground is thus broken through conductor 113 and the current flows to ground through the electromagnet 69 which is again energized. The plunger is thus drawn up, shutting off communication between the chambers 115 and 116 and preventing any further venting of the train pipe pressure.

Accordingly, when the train runs past the danger signal the brakes are applied until the speed reaches a predetermined amount,*. say six miles per hour, whereupon the brakes are again released, permitting the brakes to be released in case the block ahead and 63 and also relay 58, whose'armature 59 is drawn down by the spring associated therewith. This disconnects the negative side of battery 56 from .both shoes 45 and 46' so that there is no return circuit "from ground to the negative side of the battery. Consequently the electromagnet winding 69 of the brake valve will be deenergize'd and the train pipe 117 entirelyvented tofully apply the brakes and stop the tra n.

heoperation of the "system as a wh l i briefly as follows: H When theltrack 's clear both'of the semaphores .31 *a'nd1-32aref in upright position 120 and the circuits of all therelays 15,29-and' g '30" are energized so that the circuitsofithe; electromagnets. 1, 2, 3 and4 are openland devices on any train passing through'the block will accordingly not be operated and no signals will be given. a I v If there is a train in the blockat the-left of the point 3 but at the far end thereof,

so that only the semaphore 31, is down, the

circuit of relay 15 will be opened and the circuit of the electromagnet 1 closed, so that said electromagnet is energized. When a train enters the block illustrated under these conditions, the shoe 45 is drawn down bythe electromagnet, thereby deenergizing the relays 61 and 78 on the train and energizing the caution signal '53 to inform the engineer that there is a train in the block ahead.

If the train in the block ahead is near enough to cause both of the semaphores to I be down, the circuits of all the relays 15, 29

and 30 will be open and the circuits of all of the electromagnets 1, 2, 3 and 4 will be closed, so that said electromagnets will be energized and the shoes 45 and 46 on the train will be drawn down successively as the train passes the electromagnets. The shoe 45; will fir'stbe operated and the cantion signal given. As the train then runs past the electromagnet 2, the shoe 46 will be operated to denergize the relays 63, 87 and flash the danger signal and graduallyapply the brakes.

' speed of thetraln hasbeen reduced to a predetermined amount the vice will cause'the brakes to be released and allow the train to proceed if the train ahead in the next block has left said block. If, however, the train in the preceding block has not left the block, so that the electromagnets 3 and '4 are energized, then when the train proceeds past the stop electromagnets both of the shoes 45 and-46 will be slmultaneously drawn down to thereby deenergize all the relays on the train and fur- 1 p oted member 106 thereppl'ythe brakes to positively stop the train.

In order to re-set the apparatus on the train after the train has run past the caution, danger and stop signals, it is necessary for the engineer to close the manual switch 121, thereby completing a circuit fromthe battery 56 through the relay 58 and relay 61 and shoe 45 to ground and relay 63 and shoe 46 to ground. This energlzes relays 58, 61 and 63 causing'them to pick up their armatures.

he engineer also manually moves upwardly the bridging member 79 of relay 78, the bridging member 88-ofrelay 87, and the associated with relay 90. In order that this may be .easily done, the relays 78, 87 90 and the switch 121 are locgated at a convenient :point in the engine ca The switch 121 needbe closed only for an instant because, as soon as it is closed, the relay 58 is energized and the armature 59 attracted to complete the circuit to the shoes 45 and 46 and maintain said circuit closed. The switch 121 is normally biased to open position so that as soon as pressure thereon is relieved it automatically opens.

When the speed responsive detromagnet 134 may be The bridging members of relays 78 and 87 also need be held closed only an instant because as soon as they are moved upwardly the circuits of the respective relay. windings are closed, thereby energizing the relays and causing them to hold the bridging members in position.

The movable member 106 also need be held in its upward position only an instant because the relay 90 is energized and as soon as the circuit of relay 87 is completed which causes relay 90 to attract its armature 104 and lock the member 106 in position. 4

In case the direction of travel of the train is reversed, the reverse switch 66 is thrown from the position shown in Fig. 3 to the re verse position. In the latter position the relay 78 and the caution signal are connected to be controlled by the relay 63 and the shoe 46, and the relays 87 and 90 and the danger signals are connected to be controlled by the relay 61 and the shoe 45. p

A preferred construction of the shoe carried by the train is illustrated in Fig. 4. It comprises a body 125 supported at its sides on rods 126 and 127 attached to the locomotive or tender. Springs-128 are placed between the ends of the rod and the body andv between stops 129 on the rod in the body so that the shoe is spring-suspended and normally biased to assume an intermediate position, in which position the contact 130 .carried by one arm of the bell crank lever 131 is in engagement with the contact 48 connected to the conductor 62.

Theshoe may be supported from the bottom of a platform 132 illustrated in Fig. 5, which platform formsthe-bottom ofa receptacle'containing the battery for operating the relays and a switchboard 133 upon which the relays are mounted. Any other ployed. I

The construction of the electromagnets located along the track is shown in Fig. 6. These electromagnets have considerable length and are p horn type, that is; one of the poles of the electromagnet projects toward the rail and forms in effect a horn. The base of the elec attached to therail by means of a clamp, as shown, or by any other suitable means. The electromagnet is provided throughout its'length with a plurality of cores 135"around each of which is located a magnet winding. Asuitable cover 136 of non-magnetic material is provided and the space around the windings is preferably filled with oil. The horns 137 project towardthe rail so that the rail forms a part of the magnetic circuit of the magnet.

The position of the shoe 46 with reference to the magnet is shown in Fig. 5. The magnet energizes the rail sufliciently to cause the shoe to be drawn down into contact with it of a-type known as the as the train passes. In some cases the shoe may be drawn into actual contact with the rail, but in any'eventthe magnet is made strong enough to draw down the shoe at all speeds of the train sufficiently to cause the switch 47 to open its circuit.

A switch 138 is provided for maintaining the circuit closed as the reversing switch 66 is thrown from one position to the other. This switch is normally biased .to open position.

v This system avoids the use of insulated rail sections whichare generally expensive and diflicult to maintain. There are no shoes which eontinuallv slide on the rail. In' fact, the operation ofthe system does not depend upon a sliding contact between a shoe on the train and a rail or a rail section along the track. Instead it merely depends upon the drawing down or the movement of a. shoe carried by the train by means of an electromagnet or other suitable means along the track. This shoe need not be drawn to actual engagement with the devices along the track but need be only moved sufficiently to open the circuit on the train.

It is to. be understood that the structure shownis for purposes of illustration only and that Jvariations may be made therein and other structures devised which come within the spirit and scope of the appended claims.

I claim- V 1. A train control system comprising an matic track signal mechanism having caution and danger positions, a caution electromagnet located on one side of the railway track, a danger electromagnet located on the opposite side of the track, and stop electromagnets located on both sides of the track, said electromagnets being arranged so that the, caution magnet is energized when-the track signal mechanism is in can-i tion position and the da/nge'r and stop elec-- tromagnets are energised when the track signal mechanism is in danger P05111011, brake controlling means carried train, a caution and a danger signal on. the train, electrical circuits on the train for.

said signals andqbrake controlling means,

means on one side of the train responsive to the energized caution electromagnet for controlling pm. electric circuits to operate the caution; s gnal trollingllthe electric circuits to operate the danger-" signal and apply responsive mechanism carried by the train for releasing the brakes when the train speed decreases to a predetermined limit, the mechanisms carried by the train for controlling the electrical circuits being arranged so that both are operated by the trolling means,

by-the on the train, means on the opposite-sideof the trainresponsive to the energized danger electromagnet'forcow' the brakes, speed I stop electromagnets to further apply the brakes after release thereof by the speed responsive mechanism.

2. A train control apparatus comprising a brake operated means on the train, a normally closed circuit including a magnet for preventing the operation of the brake conin parallel in said closed circuit and arrangedto be responsive to devices along the track for interrupting the normally closed circuit, two signal devices on the train, a normally open circuit through each of said signals, means for closing one of said open circuits on the operation of one of said mechanisms, and means for closing the otheropen circuit upon operation of the other controlling mechanism.

3. Train control apparatus comprising an electromagnetic brake controlling valvve, a circuit for controlling said valve normally maintained closed by two movable mechanisms carried by the train and connected in parallel to the closed circuit, said mechanisms being responsive to devices along the track, a caution and a danger signal on the train, normally open electric circuits for said signals, means for closing the circuit of the caution signal when one of the mechanisms is energized to open its branch of the normall closed circuit, and means for closing the circuit ofi the danger signal when the second mechanism is subsequently operated to open its branch of the normally two mechanisms connected closed circuit, the simultaneous operation .7

of both mechanisms opening both branches brakes, an electromagnet for holding said valve closed, a closed electric circuiton the train normally energizing said magnet, said circuit having branches, movable means'carried by the train arranged to be movedby devices along the track-for interrupting one branch of said normally closed circuit, a

second movable means arranged-to be operated by devices along the track for interrupting a second branch of said normally,

closed circuit, a caution signalon the train, a normally open circuit throughsaid caution signal, a danger signal onjthe train, a

normally open circuit through said danger signal," and means for closing the circuit of the caution signal when the first movable means is operated to interrupt its branch of the normally closed circuit, and means for closing the circuit of the danger signal when the second movable means is operated to interrupt the second branch of the normally closed circuit, the interruption of caution signal, a

both branches of the normally closed circuit serving to completely interrupt said circuit and allow the brake valve to open to cause the brakes to be applied.

5. A t-raiucontrol apparatus comprising a brake valve normally biased to ventthe train pipe pressure to apply the brakes, an electronlagnetfor holding said valve closed, a normally closed circuit for sa1delectromagnet having two branches, eachof said branches having means therein by which it may be interrupted; movable magnetic shots connected to said inteirupting means and responsive to energized 'electromagnets along the track whereby as the train passes the electromagnets the shoes are operated to open the circuits, a caution signal on the train, a normally opened circuit for the danger signal on the train,

a normally open circuit through the danger,

and means for closing the circuit through-the caution signal when the first shoe is operated to interrupt its branch of the normally closed circuit, and means for closing the circuit of the danger signal when the second shoe is operated to interrupt the second branch of the normally closed circuit, the interruption of both branches completing the interruption of the normally closed circuit and thereby deenergizing the electromagnet to allow the brake control valve to vent the train pipe pressure and apply the brakes.

In testimony whereof I have hereunto set my hand.

signai,

STElVART D. RODGERS lVitnesses:

GLENN H. LnREsoHE, A. E. JOHNSON. 

